Apparatus for conditioning air



May 31,1938. BEMILLS 2,119,338

APPARATUS FOR CONDITIONING AIR Filed Sept. 24, 1934 2 Sheets-Sheet l May31, 1938. B. E. MILLS APPARATUS FOR CONDITIONING AIR Filed Sept. 24,1934 2 Sheets-Sheet 2 2,119,33t PAATUS lFiHiR ECQNDIIEEUUG R a n. Mills,carries, llllL, assignor it li/iillis Novelty iloinpany, @hicago, iii, acorporation v of llilinois application September 24, 19341, Serial No.'ii5,lii5

t illlaims.

This invention relates to an improved apparatus for conditioning air,and particularly to an apparatus for cooling, and regulating themoisture content of, the air to be treated, by the use of a solidifiedrefrigerant such as carbon dioxide.

One of the important objects of the invention is to provide an apparatusfor emciently utilizing a refrigerant, such as solidified carbondioxide. for the cooling of air in ofiices and similar places where itwould not be practical or feasible to use a costly compressor-condensertype of refrigerating equipment.

Another object of the invention is to provide an air conditioningapparatus wherein a mass of solidified refrigerant, such as carbondioxide, is efficiently utilized to cool the air through the provisionof a plurality of air flow tubes which are submerged in a body of liquidwhich is maintained in contact with the mass of refrigerant, the liquid,by reason of its complete contact with the exterior surfaces of saidtubes, providing an almost perfect medium for transfer of heat betweenthe walls of the tubes and the mass of refrigerant.

Another object, of the invention is to provide a cooling apparatus ofthe character set forth in which the cooling tubes through which the airis circulated are arranged to operate as condensers for removingmoisture from the air during the course of its passage through thetubes, thereby reducing the humidity. of the air in the .room as well ascooling the same to a comfortable degree.

A further object of the invention is to arrange the cooling tubes insuch position that the moisture forming therein will bedrained from thetubes and automatically removed from the path of air flow.

A still further object of the invention is to provide in an airconditioning apparatus of the type specified, means for regulating theexwnt to which the mass of refrigerant is immersed in the body ofliquid, thereby adapting the apparatus to variations in the rate of'cooling, depending upon the volume of air being treated.

Other objects and advantages of theinvention will be apparent from thefollowing detailed description taken in connection with the accompanyingdrawings wherein I have shown the preferred form in which I have thusfar contemplated applying the principles of the invention.

Referring to the drawings:

Fig. 1 is a front elevational view of a cabinet (ill. 62-915) embodyingthe improved air conditioning apparatus, portions of the front wall ofthe cabinet being broken away to show the construction of the coolingtubes and the liquid level adjusting mechanism;

Fig. 2 is a top plan view of the cabinet, the

j top wall of the cabinet being broken away to show the construction ofthe inner top wall;

' I Fig. 3 is a horizontal section through the cabinet taken on line 3-3of Fig. l; and

Fig. 4 is a vertical section through the cabinet taken on lined-t ofFig. 1.

Referring to the drawings in detail, the apparatus in the embodimentshown is embodied in a double walled cabinet consisting of a rectangularbase 5, a pair of spaced front walls 5 and I, a similar pair of spacedback walls t and t, side walls I i and i2 extending between the innerpair of walls i and 9, and outer side walls l3 and I4 extending betweenwalls 6 and t and spaced from walls I I and I2, respectively. The

edge portions of the inner vertical walls are flanged outwardly asindicated at it, these.

flanged portions being either welded or riveted to the adjacent upperedge portions of the outer walls. The packing of insulating material isthus completely enclosed and serves to efiectively pre-' venttransmission of heat to the interior of the .cabinet.

In accordance with my invention I provide in the cooling cabinet aplurality of air flow tubes 2i which are preferably formed of sheetmetal. As shown in Fig. 4, these tubes extend between walls I and 9, theends of the tubes being welded as indicated at 22 to the circumferentialedges of openings which are formed in walls I and 9 to receive the endsof the tubes. The portions of the outer vertical front wall 6 whichregister with the ends of tubes 2| are cut away to provide openings 23,and the lower por tion of back wall 8 opposite the bank of tubes 2| iscut away to receive a fan jacket 24 which is riveted at 20 to wall 8.Air is circulated through tubes 2| by a fan 25 which is driven by anelectric motor 26, the latter being removably secured by a series ofbolts 21 -to casing 24, said casing being provided with openings 28through which air may pass to the tubes 2|. If preferred, the blowerunit consisting of -fan 25 and motor 28 may be made entirely separatefrom the cabinet. In fact an ordinary electric fan may be used for thispurpose by merely placing it opposite the tube openings in rear walls 8and 3.

The apparatus is designed to cool the air during its passage throughtubes 2| under the action of fan 25. In the embodiment shown I employ amass of solidified carbon dioxide 28 which is supported in the cabinetabove tubes 2| on a screen 3|, the latter being supported in the cabineton a pair of angle bars 32 and 33 which are secured to walls 1 and 9,respectively. In accordance with one of the important features of theinvention, the mass of solidified carbon dioxideor dry ice 29, insteadof being placed in direct contact with tubes 2|, is supported in theupper portion of the cabinet, as shown in Figs. 1 and 4, and a path forflow of heat from the walls of tubes 2| to the mass of refrigerant isprovided by a body of liquid 34 which extends from the bottom of thecabinet to level slightly above screen 3|. The purpose of this liquid isto provide for a more perfect path for flow of heat through the walls oftubes 2| to the mass of refrigerant than would be obtainable if therefrigerant were simply placed in direct contact with the exterior-wallsof said, tubes. In the case where dry ice is employed as' therefrigerant,

I find that denatured alcohol is a suitable liquid.

to use for this purpose. In general it may be said that the liquidusedmust be one which has a freezing point below the melting point of theparticular refrigerant employed. Also the liquid should be one in whichthe refrigerant will readily dissolve.

An apparatus of this type, which uses an expendable refrigerant, mustnecessarily be designed to operate for a period of several hours, orpossibly a day, without requiring replenishment of the refrigerant. Inthe embodiment shown, in which the apparatus is especially designed forthe use of dry ice, I find that most eillcientuse of the refrigerant isobtained by adjusting the level of liquid 34 so'that it has but veryslight contact with the mass of refrigerant, it being noted from Figs. 1and 4 that the surface of the liquid 34 is but slightly above screen 3|.As previously explained, the bodyof liquid serves as a cooling bath forextracting heat from the walls of tubes 2| and it is usually unnecessaryto have any substantial portion of the mass of refrigerant immersed inthe liquid.

At ordinary pressures solidified carbon dioxide vaporizes withoutpassing through the intennediate liquid stage. The carbon dioxide gas isre moved from the cabinet through a vent pipe 35 which is positioned inthe upper portion of the rear wall of the cabinet. The top of thecabinet is closed by a sheet metal cover plate 36, and an inner coverplate 31, formed of suitable insulating material, is provided forsealing the refrigerant compartment, this cover being provided at itsrear edge with a pair of cleats 39 which are received in sockets formedin the rear wall of the cabinet. The. front edge of cover 31 is providedwith sliding latch members 41 which are secured in position by channelstrips 42. The cover 31 is locked in position by inserting cleats 39 inthe rear cabinet wall after which the sliding latch members 4| are movedoutwardly into locking position against the front wall as shown in Fig.2.

By locating the vent tube 35 at the top of the refrigerant chamber (thespace defined by walls 9, top 36, and screen 3|) and keeping the lattercovered, a blanket of vaporized carbon dioxide is constantly maintainedaround the entire body of unmelted refrigerant, insulating the same fromsuch heat as may find its way to the inner walls 9. At the same time,the excess (and least cold) carbon dioxide is allowed to flow ofl, whilethe colder portion of the carbon-dioxide blanket, remains in thechamber.

By maintaining the body of solid refrigerant completely above and spacedfrom, the air tubes 2| it is possible to use solid cakes of the refrig-qerant of large enough size to fill the refrigerant chamber, and theconduction of heat thereto from all of the tubes 2|, will be uniform.This is of particular importance in connection with the use ofcarbon-dioxide ice, because of the great difference between thevaporizing temperature of the latter and the temperature to which theair is to be cooled. It is undesirable to have direct contact betweenthe, air-flow tubes and the solid refrigerant. Maximum coolingefliciency can be obtained by cooling all of the tubes touniform'temperature, keeping the body of solid refrigerant insulatedfrom heat absorption by the enveloping blanket of carbon-dioxide gasabove it and on 'allsides, and limiting its heat absorption to thecontact'of its bottom with the liquid which carries the heat uniformly'from all of the tubes.

Means for varying the extent of immersion of the mass of dry ice 23 inthe liquid 34 is provided-whereby to regulate the container, to thecooling of a greater or less volume of air as may be desired. In theembodiment shown I provide jects from the side wall of thecabinet. Byturning crank 48, panel 43 may be raised or lowered in the body ofliquid 34, thereby changing the liquid level to regulate the extent ofimmersion of the mass of dry ice 29. If air is being circulated throughtubes 2| at a comparatively rapid rate, it may be desired to have themass of refrigerant 29 immersed'to a considerable extent in liquid 34.On the other hand, if the cooling demand is comparatively light, panel43 may be raised to produce a correspondingly lower liquid level and aconsequent lessening in the rate at which" the refrigerant is expended.

I find that by cooling the air through the use of tubes 2| in the mannerdescribed I am able to likewise control the relative humidity of theair, thereby preventing an oppressive increase in the moisture contentof the air upon a lowering in the temperature. Figs. 1 and 4 that theuse of a plurality of tubes 2| arranged as shown, provides a very largesurface which the air may contact during its passage through thecabinet. As the temperature of the air falls, the saturation point forthe lower temperature is reached, with resultant condensation ofmoisture on the walls of tubes 2|. I find that this condensation issuflicient to prevent the It will be apparent from.

aliases air from becoming excessively humid even where the temperaturedrop is as much as 40 F. In order to remove the condensed moisture fromtubes 2| I arrange the latter in inclined position as shown in Fig. 4.With the tubes in this position the moisture will drain toward theforward ends of the tubes, and will then flow downwardly along wall Iinto a drip pan 49, which is placed below the cabinet. The condensedmoisture is months. Under such conditions the outlay requiredl for amechanical refrigerating unit would be prohibitive.

The foregoing detailed description has been given for clearness' ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible in view of the prior art.

What I regard as new and desire to secure by Letters Patent is: r

1. Air conditioning apparatus comprising, in combination, a cabinet, aplurality of air flow tubes extending transversely through said cabi-.net near the bottom thereof, the lower'portion of the cabinet enclosingsaid tubes being adapted to hold a body of liquid extending to a levelabove the uppermost of the tubes, means for supporting a mass of asolidified refrigerant in the cabinet above said tubes and in positionto be partially submerged by the liquid contained in the lower portionof the cabinet, and means for regulatlng'the extent of immersion of themass of refrigerant in said liquid.

2. Air conditioning apparatus comprising, in

combination, a cabinet, a plurality of air flow tubes extendingtransversely through said cabinet near the bottom thereof, the lowerportion of the cabinet enclosing said tubes being adapted to hold a.body of liquid extending to a level above the uppermost of the tubes,means for support ing a. mass of a solidified refrigerant in the cabi- 1net above said tubes and in position to be partially submerged by theliquid contained in the lower portion of the cabinet, and meanscomprising a vertically movable fluid displacing memher for varying thelevel of liquid in the cabinet whereby to regulate the extent ofimmersion of said mass of refrigerant in the liquid.

3. Air' conditioning apparatus comprising a receptacle having aplurality of air flow tubes extending transversely therethrough; meansfor supporting a mass of a solidified refrigerant in said receptacleabove said tubes, a body of liquid disposed in said receptacle aroundthe tubes and in contact with a portion of the mass of refrigerant, thefreezing point of said liquid being below the melting point 'of therefrigerant, and

means for regulating the extent of ersicn oi the refrigerant in saidliquid.

4. Air conditioning apparatus comprising, in combination, a cabinet, a.plurality of air flow tubes extending transversely through said cabinetnear the bottom thereof, the lower portion of the cabinet enclosing saidtubes being adapted to hold a body of liquid extending to a level abovethe uppermost of the tubes, and means for supporting a mass of solidcarbon dioxide in the cabinet spaced above the uppermost of said tubesand in position to be partially submerged by the liquid contained in thelower portion of the cabinet.

5. Air conditioning apparatus comprising, in combination, a cabinet,.plurality of air flow tubes extending transversely through said cabinetnear the bottom thereof, the lower portion of the cabinet enclosing saidtubes being adapted to hold a body of liquid extending to a level abovethe uppermost of the tubes, means for supporting a mass of solid carbondioxide in the cabinet spaced above the uppermost of said tubes and inposition to be partially submerged by the liquid contained in the lowerportion of the cabinet, and

means for circulating the air to be treated through said tubes.

. a body of liquid disposed in said receptacle around the tubes and incontact with a portion of the vmass of refrigerant, the freezing pointof said liquid being below the melting point of the refrigerant, andmeans for circulating the air to be treated through said tubes.

7. Air-conditioning apparatus comprising: a cabinet, a plurality ofair-flow tubes extending transversely through the lower region of saidcabinet, a refrigerant chamber being formed above said tubes, saidchamber being closed on all sides and at the top, and of such dimensionsas to receive a. mass of carbon-dioxide ice and provide a closed spacearound all sides of and above said mass, means'to support said massabove and out of contact with said tubes, and means for withdrawing thevapor, resulting from vaporization of said mass, from the upper regionof said chamber, the region of said cabinet below said chamber beingadapted to hold a body of liquid extending to a level in contact withthe bottom of said mass, forming the bottom of said closed space inwhich said vapor is confined in the form of an insulating blanketenveloping all sides or said mass except its bottom.

8. Air conditioning apparatus comprising, in combination, a cabinet, aplurality. of air flow tubes extending transversely through said cabinetnear the bottom thereof, the lower portion or the cabinet enclosing saidtubes being adapted to hold a body of liquid extending to a level abovethe uppermost of the tubes, and means for supporting a mass of solidcarbon dioxide in the cabinet spaced out of contact with said tubes andin position to be partially submerged by the liquid contained in thelower portion or the cabinet.

BERT E. MILLS.

